springMVC下載模板檔案（不跳頁面）

 @RequestMapping("/xiazai")  
    public void xiazai(HttpServletRequest request,  
            HttpServletResponse response) throws Exception {  
        response.setContentType("text/html;charset=UTF-8");   
        BufferedInputStream in = null;  
        BufferedOutputStream out = null;  
        request.setCharacterEncoding("UTF-8");  
        String rootpath = request.getSession().getServletContext().getRealPath(  
                "/");  

        System.out.println(rootpath+"路徑");
        String fileName = request.getParameter("f");  

        System.out.println(fileName);

        fileName="model.xlsx";
        try {  
            File f = new File(rootpath + "template/" + fileName);  
            response.setContentType("application/x-excel");  
            response.setCharacterEncoding("UTF-8");  
              response.setHeader("Content-Disposition", "attachment; filename="+fileName);  
            response.setHeader("Content-Length",String.valueOf(f.length()));  
            in = new BufferedInputStream(new FileInputStream(f));  
            out = new BufferedOutputStream(response.getOutputStream());  
            byte[] data = new byte[1024];  
            int len = 0;  
            while (-1 != (len=in.read(data, 0, data.length))) {  
                out.write(data, 0, len);  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            if (in != null) {  
                in.close();  
            }  
            if (out != null) {  
                out.close();  
            }  
        }  

    }